Many days, he says it was the only choice he had if he wanted to eat, growing up in poverty in Hawaiian Gardens, Calif., and Guadalajara, Mexico.

Mares (25-0-1, 13 knockouts) has always competed like a hungry fighter, using a brawling style to win matches and please crowds. He defeated top fighters to claim titles at bantamweight and junior featherweight and is now on the cusp of stardom.

With a slot on Saturday's Showtime PPV card at the MGM Grand Garden Arena in Las Vegas, headlined by the Floyd Mayweather Jr. vs. Robert Guerrero welterweight title fight, Mares will have a chance to considerably raise his stock. He's moving up to 126 pounds to face WBC featherweight champion Daniel Ponce de Leon in his quest for a title in a third weight class.

"With all due respect to Mayweather, I plan to steal the show and make it my night," Mares, 27, told USA TODAY Sports.

"It's amazing to be on an undercard of Mayweather's — he brings in great fans, a great audience. I'm going to be in the spotlight, so I have to take advantage of it."

When Mares was 15, he set out alone on an odyssey to his homeland. His parents gave him what little money they had in hopes he could represent Mexico in the 2004 Olympics in Athens. Though he failed to medal, Mares realized his Olympic dream, an experience that forced him to "grow quick and fast."

Upon returning to the USA, Mares turned pro at 19. In 2010, he made his Showtime Championship Boxing debut against Yonnhy Perez, fighting to a majority draw in his first bid for a world title. Mares continued to fight exclusively on Showtime (six fights total), reeling off victories against the likes of Anselmo Moreno, Vic Darchinyan and Joseph Agbeko (twice), proving to be one of the best fighters in the sport.

Showtime Sports executive vice president Stephen Espinoza is impressed with Mares and says he is "poised to make a big jump into the spotlight."

"He's been one of the stalwarts of the Showtime lineup. He's deserved every minute of the exposure he's given," said Espinoza, who took over as head of Showtime Sports in November 2011. "He's a really personable kid. He fights his heart out every time; he consciously goes out to entertain. Given his progression, particularly over the past 18 months, he's really on the cusp of becoming a widely known star."

To continue his climb, Mares will have to get past 32-year-old Mexican Ponce de Leon (44-4, 35 KOs), a devastating southpaw. "He's a come-straight-forward guy, he has a crafty style — a unique style," said Mares, who is friendly with Ponce de Leon out of the ring. "He throws a lot of punches, and he hits hard. He's a puncher. But he is a slow fighter. I have to be careful with his aggression and his power punches."

If all goes according to plan Saturday, perhaps Mares one day will headline pay-per-views, much like his promoter, Oscar De La Hoya.

"The fights are there. I'm fighting top, elite fighters," Mares said. "From the boxing side, I think I have it all. I've proven myself. But I have to win on Saturday night and keep pushing, and hopefully I get a bigger fight after this."